1. Technical Field
This invention pertains generally to the field of computer network management, more particularly to increasing bandwidth utilization in wide area networks. This invention further pertains to a method of dynamically varying the bandwidth allocation for data coming from regions into a wide area network and an apparatus that implements the method.
2. Description of the Prior Art
The concept of wide area networks has evolved steadily in the field of computer networking. The need for global networking has resulted in the use of high-speed backbones that connect large metropolitan areas. Most installations utilize high-speed connections that connect a plurality of add-drop multiplexers to form the wide area network. The add-drop multiplexers are usually organized in the form of a ring. In a typical installation, an add-drop multiplexer services a region within the metropolitan area. The add-drop multiplexer is connected to a router. The router fans out network connections to users within the region.
Data from one region that must be delivered to another region is collected by a router and then delivered to the add-drop multiplexer affiliated with the first region. This first add-drop multiplexer injects the data into the ring. The data propagates through the ring to a second add-drop multiplexer where this second add-drop multiplexer services a different region. The second add-drop multiplexer extracts the data from the ring and forwards the data to a router that fans network connections within the second region.
The data ring formed by the add-drop multiplexers typically propagates data at extremely high-speed and at a constant data rate. Given the nature of the data ring, the amount of data that can be transmitted around the ring is usually a constant bandwidth. In order for a add-drop multiplexer to inject data into the ring, it must have a predefined allocation of bandwidth. If the cumulative bandwidth egressing from a region exceeds the bandwidth allocated to that region's add-drop multiplexer, the data may be dropped or delayed pending on the management strategy imposed on the data ring.
Up until now, the amount of bandwidth allocated to each add-drop multiplexer, i.e. to each region, is determined by monitoring data traffic patterns over some period of time. Monitoring data traffic patterns is accomplished at a network management center. Human intervention is required in the management process to determine what level of bandwidth must be allocated to each region. The bandwidth allocations may vary with each hour of each day so that a fair and reasonable bandwidth leveling can be achieved.
Once bandwidth allocations for each region are established, these bandwidth allocations must be conveyed to each add-drop multiplexer in a metropolitan area. This is typically accomplished by a direct connection from the network management center to each add-drop multiplexer. The add-drop multiplexers that year to their respective bandwidth allocations until a new allocation level is received from the network management center.
One significant problem in the known bandwidth allocation scheme is that bandwidth allocations are infrequently updated. Exasperating this problem is the fact that bandwidth allocations are established based on past network traffic. In the known art, there is simply no capability to modify bandwidth allocations on the real-time basis. This means that a region may need more bandwidth minutes present allocation where the same time a different region may not require all of the bandwidth of its current allocation. Hence, the data ring can be under utilized from the perspective of one region while at the same time appear to be bogged down from the perspective of the different region. On balance, this problem manifests itself in the form of ineffective bandwidth utilization at each add-drop multiplexer.